The present invention relates to the device for guiding the gripper bars of a double-gripper weaving machine. In the case of such weaving machines provision is made along both sides of the shed formed between the warp threads for a device for driving and a device for guiding two gripper bars lying one above the other. A gripper is situated on the end of each gripper bar.
By driving the gripper bars -- which are situated and move in pairs in line with each other along both sides of the weaving machine -- to and fro, the grippers lying in line with each other are taken for each pick simultaneously along both sides of the fabric into the open shed, a weft thread being taken along by one of the grippers and in the shed passed on to the other gripper at the place where the two grippers meet, following which both grippers are pulled back out of the shed, so that the weft thread in the end is pulled from one side of the fabric to the other side, through the shed. This cycle is repeated each time a shed is formed, a weft thread being taken in each case from one side of the fabric to the other and woven with the warp threads. The drive of the gripper bars is preferably carried out by means of drive gear wheels which mesh with toothed sides of said gripper bars.
Guide means also have to be provided for each gripper bar, so that the grippers cover the desired path during their to and fro movement. A known guide device is described in Belgian Pat. No. 8,701,166.
This gripper guide comprises, on the one hand, a number of rollers which are situated at the level of the drive gear wheel with their cylindrical surface against the gripper bars, in such a way that the gripper bars move between the rollers and their respective drive gear wheel. These rollers guide the gripper bars in such a way that they interact well with the drive gear wheel. This known gripper guide also comprises two guides contoured in an L-shape, each of which is provided to guide one of the gripper bars which in this case, being provided with a slipper on their ends, glide to and fro in the angle formed by their L-shaped guide, while the horizontal part of the guides is situated below the gripper bars.
The known gripper guide also comprises two guide tables which are provided to guide the gripper bar heads. These tables are fixed so that they are adjustable in height, weft direction and warp direction.
The above-mentioned parts of this gripper guide are each interconnected adjustably to form one unit, while the unit is adjustably connected to the frame of the weaving machine. The guides are each accommodated so that they are adjustable in height in a channel section which is fixed to the gripper guide housing. The gripper guide housing can rotate relative to the drive shaft.
A disadvantage of this gripper guide lies in the fact that, due to the L-shaped guides, the gripper bars are guided only along the bottom side and the rear side, as a result of which they swing forward on their to and fro movement. The result of this is that the roller guide operates operates jerkily, causing uneven wear to occur on the back of the gripper bars. The backs of the gripper bars become uneven, so that the guide rollers absorb increasingly strong impact forces. The bearings of the guide rollers are consequently subjected to great wear, so that these bearings in the end become defective after quite a short period of operation.
Another disadvantage of this gripper guide is that the play between the drive gear wheels and the corresponding gripper bars is difficult to set. For, the L-shaped guides are only (jointly) rotatable relative to the gripper guide housing, in addition to their common adjustability in height. This gives rise to another disadvantage, namely that individual setting of the gripper guide for each gripper bar separately is not possible.